EDEM as an acceptor of terminally misfolded glycoproteins released from calnexin

Terminally misfolded proteins in the endoplasmic reticulum (ER) are retrotranslocated to the cytoplasm and degraded by proteasomes through a mechanism known as ER-associated degradation (ERAD). EDEM, a postulated Man8B-binding protein, accelerates the degradation of misfolded proteins in the ER. Here, EDEM was shown to interact with calnexin, but not with calreticulin, through its transmembrane region. Both binding of substrates to calnexin and their release from calnexin were required for ERAD to occur. Overexpression of EDEM accelerated ERAD by promoting the release of terminally misfolded proteins from calnexin. Thus, EDEM appeared to function in the ERAD pathway by accepting substrates from calnexin.     

Physiological difference between free and triglyceride-type conjugated linoleic acid on the immune function of C57BL/6N mice

Previous studies have shown the physiological significance of dietary conjugated linoleic acid (CLA) in various experimental animals and in human beings. One of the important problems to better elucidate is the difference between triglyceride (TG) and free (FFA) dietary CLA. Here, using splenocytes, this study assesses how TG- and FFA-CLA modulate immunoglobulin and various cytokine productions. In this study, C57BL/6N mice were fed an experimental diet containing 0% CLA, 0.1 or 1% FFA-CLA, or 0.1 or 1% TG-CLA for 3 weeks. The production of immunoglobulin tended to be up-regulated by 1% FFA-CLA. As a result of protein array analysis using the supernatant from splenocytes cultured with no CLA, 1% FFA-CLA, and TG-CLA, some cytokine production was shown to be remarkably regulated by dietary FFA- and TG-CLA. A total of 32 cytokines were examined, and 11-14 produced cytokines that were 2-fold up-regulated as compared with control for FFA- or TG-CLA, respectively. Especially, the production of IL-9 and MCP-5 and other cytokines was remarkably up-regulated by both FFA- and TG-CLA. In addition, seven cytokines were 2-fold down-regulated by TG-CLA. These data show that there is a slight but significant difference between the functionalities of FFA- and TG-CLA.     

Studies on the organo-mineral colloidal complexes of paddy soil II

In the preceding paper (1) the authors reported the humus status in the organo-mineral colloidal complexes of the degraded paddy soils, which is characterized by the leaching of active iron, manganese and the other elements such as silica, magnesium and phosphoric acid from the furrow slice (2). And it was concluded that the organo-mineral colloidal complexes (Gl colloidal complexes) of the degraded paddy soil is characterized by the marked accumulation of humus, especially the readily soluble humus as compared with those of the normal.     

Effectiveness of tetrazolium salts in microbial ecological studies in submerged soil

Several trials to obtain information on the living microorganisms at micro-sites of the submerged soil by the novel utilization of the tetrazolium salts were described. Results are summarized as follows:

(1) The air-dried soil was incubated with TIC (triphenyl tetrazolium chloride) under submerged condition according to the modified double layer plate method. The red formazan (the reduced product of TIC) was precipitated at the biologically active sites by the dehy. drogenase activity. Using a binocular microscope, most of the biologically active sites were found to be localized on and around the organic debris.

(2) The amount of nitrogen mineralized by incubating the soil under submerged condi. tion correlated well not only with the amount of formazan formed biologically in the submerged soil but also with the amount of formazan formed non-biologically by heating the soil with TIC in Ba(OH). solution. In addition, the pattern of precipitation of the nonbiologically formed formazan was very similar to that of the biologically formed formazan. Accordingly, the substances which reduced TIC non-biologically were considered to be closely associated with the substrates for the microorganisms.

(3) The plant debris stained with the red formazan could be mounted on a slide glass and observed at high magnification for the detailed study on the process of decomposition. Addition of lactophenol cotton blue to the plant debris could visualize the microorganisms responsible for the decomposition of the plant debris.

(4) NTB (nitro tetrazolium blue) was the most suitable for staining individual microorganisms growing on cellulosic materials or plant debris. The double staining with NTB and rosebengal made the discrimination between dead or resting cells and viable ones possible when this technique was applied to the decomposed filter paper.     

Nitrogen isotope fractionation during nitrogen transport from ectomycorrhizal fungi,Suillus granulatus,to the host plant,Pinus densiflora

The ¹⁵N natural abundance in Pinus densiflora Sieb. et Zucco that had been inoculated and not inoculated with ectomycorrhizal fungi (Suillus granulatus (L.:Fr.) O. Kuntze) was compared. The inoculated pine needles showed a lower δ¹⁵N value, while the uninoculated ones showed a higher δ¹⁵N value. Higher δ¹⁵N values in the mycelial mat of the ectomycorrhizal fungi compared to those of the inoculated pine needles were also observed. These facts indicate that nitrogen isotope fractionation occurred during the nitrogen transport from mycorrhizal fungi to the host plants.     

Effect of monosilicic acid on hydrolytic polymerization of Fe(III) and structure hydrolytic products

To analyze the mechanism of retarded hydrolytic polymerization of Fe(III) and crystallization of the hydrolytic products in the presence of H₄SiO₄, we measured the changes in the monomeric Fe(III) concentration as a function of pH, H₄SiO₄ concentration, and aging time, and characterized the hydrolytic reaction products by a combination of methods. The monomeric Fe(III) concentration in solutions with higher H₄SiO₄ concentrations was significantly higher than that in an Si-free solution but the differences gradually narrowed with aging time. Chemical equilibrium calculation showed that the concentration of the FeH₃SiO₄ ²⁺ complex was not high enough to account for the reduced rate of hydrolytic polymerization. Electron microscopy and infrared spectroscopy showed that the hydrolytic products were ferrihydrite or Si-containing ferrihydrite and their particle size decreased with increasing H₄SiO₄ concentration. On the basis of these observations, we concluded that the interfering effect of H₄SiO₄ on the hydrolytic polymerization involved two mechanisms: 1) the coexistence of H₄SiO₄ delayed the kinetics of the hydrolytic polymerization of Fe(III) to a certain extent due to the formation of an FeH₃SiO₄ ²⁺ complex, and 2) H₄SiO₄ retarded the growth of Fe(III) hydroxides by binding onto the active sites of the hydrolytic products.     

Demerium exchange of hydroxyl groups in allophane

The nature of amorphous silicates, allophane,ö The name allophane is used in this paper in a dual sense; the one stands for a group of amorphous or nearly amorphous aluminum silicates associated with minor amounts of other metals, and the other in some restricted sense for amorphous silicates other than imogolite. The latter term, imogolite, is used for convenience to denote a component that shows broad x-ray diffractions at 14 (strong), 7.6 (medium) and 5.6 (weak) Å, gives an endotherm at 430°C, and appears as thread-like particles of diameter 100 to 200 Å in electronmicrographs (21). as a main clay constituent determines many of the physical and chemical properties of volcanic ash soils. Recent developments in the study of allophane together with other amorphous inorganic materials in relation to their nature and occurrence in soils have been reviewed by MITCHELL et al. (12).     

Factors Influencing the Determination of Microbial Biomass-Nitrogen in Submerged Soil

In a previous paper (1), a modification of the chloroform fumigation method (2) was proposed for estimating microbial biomass-nitrogen (N) in submerged soil. It was found that a large part of the living bacteria in the submerged soil was killed within about 12 h of the fumigation and was actively mineralized by subsequent anaerobic incubation.

In this paper, the following factors which influence the estimated amount of microbial biomass-N were examined: a) inoculation to fumigated soil, b) duration of anaerobic incubation, c) storage and sieving pretreatments of soil, and d) effect of fumigation on soil organic matter.